1. Field of Invention
The present invention relates to a drive system for motor-driven appliances. In particular, the invention relates to a mechanical four-speed drive system or gearbox for household appliances in which the system has two drive-outlets.
2. Background
In traditional household appliances, such as juice extractor, blenders, meal makers, stir cookers, food processors, soymilk makers and soup makers, and so forth, a common construction among such appliances is where a motor is fixed in a unit base, the motor shaft is mounted with a coupling, the blade or tools are directly assembled to the drive outlet, and the motor rotates at a speed that directly drives the blade or tools to process the foods. Since different foods need different processing speeds, traditional household appliances have a speed adjustment switch, but its speed is changed by variable voltage. Although it saves energy, it is very low in reliability, output torque is decreased, speed is unstable, and it can only process soft foods. The harder foods are very difficult to process, aggravating and damaging the motor as well as the blade or tools of the appliance.
In addition, household appliances on the market are set with two or three drive outlets that provide two or three different speeds, and can be connected to different sized blade or tools. Each drive outlet has its different speed to process food. In order to process the different kinds of foods, additional blades or tools need to be changed and connected with the particular drive outlets. During the process of changing the blades or tools, the unit needs to be stopped, excessive blades or tools need to be changed and connected with the drive outlets, which cause inconvenience and waste of time. Also, when processing hot food, changing the blades or tools is both difficult and unsafe.
Therefore, there is a need for a household appliance with a four-speed drive system that provides two drive-outlets, in which each drive-outlet can be driven at two different speeds in the same rotational direction. There is a need for such an invention in which a four-speed drive system is cooperated with a motor, three one-way bearings, and a gear system without changing the input voltage, and which is of simple construction, reliable, stable with high torque, convenient to use, and able to process various foods.